A&P 2: Endocrine Flashcards
What are the mediators that are neurotransmitters and hormones?
Norepinephrine
Epinephrine
Oxytocin- Neuro: released throughout brain and expressed by neurons. Horm: released from pituitary gland to blood, acts on breast and uterine tissue
Difference between Endo and Exo
Endo: within; secretes hormones to interstitial fluid and blood (TSH)
Exo: secrete products to ducts that are released into cavities/organ lumen or skin surface (sweat,, oil, salivary, mammary, ceruminous, lacrimal)
Receptors are made of what?
Where are they located?
Cellular proteins
Cell surface or located inside cell
Define receptor down-regulation
Too much hormone is present
Receptor reduction = decreased sensitivity
Define receptor up-regulation
Not enough hormone is present/circulating
Increased receptors = increased sensitivity
Define endocrine action
Hormone distributed by blood to distant target cells (anterior pituitary releases TSH)
Define circulatory hormones
How long do they last?
(majority) pass from secretory cells to interstitial fluid into blood stream
Minutes to hours
Define local hormones
How long do they last?
Act on neighboring cells or same cell WITHOUT entering blood stream
Paracrine- act on neighboring cell
Autocrine- act on same cell
Quick/sudden onset
Lipid soluble hormones use what molecule for transport?
Transport proteins that were synthesized in liver
Makes hormone temporarily water soluble, retards passage of smaller molecules through kidney filter to urine
Why are lipid soluble hormones longevity important?
Provides reserve of hormone in blood stream
Free fraction- percentage of hormone not bound to transport protein and can bind w/ receptors immediatley
How is control of hormone secretion regulated?
NS
Chemical changes
Other hormones
What regulates the release of epinephrine?
NS impulses to adrenal medullae
What regulates the release of parathyroid hormone?
Blood Ca2+
What regulates the release of cortisol?
ACTH from anterior pituitary stimulates cortisol release from adrenal cortex
What are the 3 major groups of hormones?
Grouped based on chemical structure
Protein/polypeptide
Steroid
Tyrosine derivative
CAN be classified by solubility, gland and function
Majority of hormones fall into what chemical structure of hormones?
Protein and polypeptide
Structure and types of protein/polypeptide hormones?
Protein- more than 100 aa joined together
Polypeptides: 3-99 joined aa
What type of solubility do protein and polypeptide hormones have?
Water soluble
Can travel unbound in blood
Receptors on cell membranes
What two hormones are released from the posterior pituitary?
ADH- increases water reabsorption by kidneys
Oxytocin- stimulates uterine contraction and milk production
What protein hormone does the thyroid secrete?
Calcitonin- decreases serum Ca levels, deposits Ca into bones
What two hormones does the pancreas secrete?
Insulin- promotes glucose-> cell movement
Glucagon- synthesis and secretion of glucose from liver
What hormone does the parathyroid gland secrete
PTH- increases Ca absorption in gut and kidneys, breaks down bone matrix to increase serum Ca levels
What two hormones does the placenta secrete?
HCG- promotes growth of corpus luteum and secretion of estrogen/progesterone
Human somat: promotes fetal tissue development
What three hormones does the kidney secrete?
Renin: angiotensinogen to angiotensin
EPO- increases RBC production
Calcitriol- increase intestinal absorption of calcium
What 2 hormones does the heart secrete?
ANP- increases Na excretion by kidney to reduce BP
BNP- reduces BP when heart is stretched too far
What hormone does the stomach secrete?
Gastrin- stimulates HCl secretion by parietal cells and growth of gastric mucous
Secreted by G cells
Stimulated by: protein ingestion, digestion, vagal stimulation
What two hormones does the small intestine secrete?
Secretin- stimulates pancreas to release bicarbonate
Cholecystokinin- stimulates gallbladder to release pancreatic enzymes
What hormones does the adipocytes secrete?
Leptin- inhibits appetite, stimulates thermogenesis
Adiponectin- reduces insulin release
What are steroid hormones derived from?
Cholesterol
Hence, lipid soluble
How do steroid hormones travel/bind to receptors?
Bound to transport proteins while in blood
Freely pass through cell membranes
Binds to receptors inside of cell
What two hormones do the adrenal cortex secrete?
Zona glomerulosa
Cortisol: control metabolism and anti-inflammatory
Aldosterone: Increases renal Na absorption, promotes K and H loss
What hormone do the testes secrete?
testosterone- secondary sex characteristics
Examples of Tyrosine Derivative Hormones
Thyroid hormones- T3, T4
Adrenal medullary hormones- (catecholamines), epi, norepi
Prolactin Inhib Hormone- aka Dopamine
Tyrosine hormones from the hypothalamus
Prolactin inhibiting hormones
Water soluble
What part of the brain controls the Autonomic NS
Hypothalamus, through neural and hormonal
How does the hypothalamus connect to the pituitary gland?
Connected to POSTERIOR Pituitary by infundibular stalk
What two structures combine to make the infundibulum
Pars tuberalis- sheath from anterior pituitary
Infundibular stalk
Every hormone synthesized in the hypothalamus is transported to where?
Pituitary for storage or other hormone synthesis
Hypothalamus + pituitary gland have control over what 4 processes?
Growth regulation
Development
Metabolism
Homeostasis
What signals does the hypothalamus respond to?
Signals from internal and external environment
Temp Hunger Satiety- feeling of being full/content BP Hormones Stress
What 3 daily rhythms does the hypothalamus control?
Melatonin secretion from pineal gland
Cortisol secretion
Body temp
Where is melatonin secreted from?
Pineal gland
Hypothalamic hormones have action where? What action do they have?
Anterior pituitary
Cause other hormones to by synthesized in ant. pit.
Function of hypothalamic releasing hormones
Stimulate release of Anterior Pituitary hormones
What are the 5 Hypothalamic Releasing Hormones
GHRH- growth hormone TRH- thyrotropin releasing CRH- corticotropin releasing GnRH- gonadotropin releasing PRH- prolactin releasing
What are the 2 Hypothalamic inhibiting hormones
Inhibit release of hormones from Ant. Pit.
GHIH- growth hormone inhib.
PIH- prolactin inhib
Growth hormone inhibiting hormones AKA
Prolactin inhibiting hormone AKA
GHIH- somatostatin
PIH- dopamine
How are hormones synthesized in hypothalamus sent to Anterior Pituitary?
Pituitary portal system (capillaries)
How are hormones synthesized in hypothalamus sent to Posterior Pituitary?
From hypothalamus to post. pit. to the infundibular stalk via AXONS
What are the 2 hormones synthesized in hypothalamus but stored in posterior pituitary?
Oxytocin
ADH
Where is the pituitary located?
Sella turcica of sphenoid bone
Anterior pituitary gland AKA
Posterior pituitary gland AKA
Ant= adenohypophysis, pars distalis Post= neurohypophysis, pars nervosa
What are the two parts of the Anterior Pituitary gland?
Pars distalis- glandular tissue
Pars tuberalis- partial coverage of infundibulum
What kind of hormones does the Anterior Pituitary make? Where do they effect?
Tropic hormones from 5 specific cell types
4 of 5 effect other endocrine glands, exception: HGH, effects almost all tissues in body, no glands
What happens to hormones once they are synthesized in the anterior pituitary?
Released into venous circulation
What are the 5 tissue types of the Anterior Pituitary?
What hormones do they secrete?
Somatotrophs: HGH Thyrotrophs: TSH Gonadotrophs: FHS, LH Lactotrophs: PRL Corticotrophs: ACTH (corticotropin), MSH (melanocyte)
HGH from Ant. Pit. AKA
Somatotropin
Characteristics of Somatotropin
Most abundant Ant. Pit. hormone from somatotrophic cells (most abundant cell)
Secreted in bursts, predominantly in first 2hrs of deep sleep
What is the main function of HGH
Promote synthesis and secretion of small protein hormones called Insulin-like Growth Factors (somatomedins)
Where are IGFs synthesized and secreted from?
Liver
Skeletal muscle
Cartilage
Bones
Changes of development within the body are believed to be due to the effects of what hormones?
Insulin-like Growth Factors, not HGH
Function of IGFs
Increase protein synthesis (uptake of aa into cells) Decrease protein catabolism Childhood growth (muscle and bones) Enhance lipolysis (increases fatty acid use instead of glucose use so neurons can use glucose)
What is the most basic carbohydrate?
Glucose
What are IGFs role during hypoglycemia
Stimulates liver to release glucose via glycogenolysis (glycogen->glucose)
When will IGFs be predominantly produced and secreted?
Low blood sugar situations
What does hypoglycemia stimulate the release of and inhibit the release of?
Stim: GHRH
Inhib: GHIH
What does hyperglycemia stimulate the release of and inhibit the release of?
Stim: GHIGH
Inhib: GHRH
What happens to blood glucose regulation during hypoglycemia?
GHRH release stim
GHIGH release inhib (hypothalamus)
Ant. Pit: secretes hGH causing increased IGF concentration
Carbohydrate metabolism and liver glycogenolysis increase blood sugar levels
What factors stimulate hGH secretion?
Hypoglycemia Sympathetic NS (stress, exercise) Deep sleep Decreased serum Fatty acids Increased serum aa Starvation/fasting Protein deficiency Increased levels of testosterone, estrogen or Ghrelin
What is Ghrelin?
Hormone released by stomach before eating
What factors inhibit hGH secretion?
Hyperglycemia Increased serum fatty acids Decreased serum aa Emotional deprivation Obesity Low T3/T4 hGH (neg feedback) GHIH Aging
What stimulates release of ACTH?
CRH from hypothalamus
Stress
Hypoglycemia
Trauma
What does ACTH control?
Cortisol production
Glucocorticoids
Androgens produced in adrenal gland CORTEX
What controls the secretion of prolactin
PRH PIH (dopamine)
Prolactin itself is weak, so what does it work with for what end result?
Estrogen Progesterone Glucocorticoids HGH T4 Insulin Milk production in pregnancy
What causes the EJECTION of milk during pregnancy?
Oxytocin from posterior pit.
What happens to PRL levels during menstruation cycle?
Low estrogen and progesterone prior to menstruration INHIBITS PIH and STIMS prolactin secretion (breast tenderness)
Rest of cycle, as estrogen increases, PIH increases, prolactin decreases
What stimulates release of FSH
GnRH from hypothalamus stimulates Ant. Pit. to secrete FSH
What effect does FSH have on female body?
Initiates follicle production
Ovarian follicular cell estrogen production
What effect does FSH have on male body?
Stimulates sperm cell production
How is FSH secretion inhibited?
Increased estrogen (females) Increased testosterone (males)
What stimulates for LH secretion?
GnRH from hypothalamus stimulates Ant. Pit. to release LH
What effect does LH have on female body?
Ovulation
Formation of corpus luteum
Secretion of progesterone from corpus luteum
FSH + LH= Estrogen secretion by ovarian follicular cells
What effect does LH have on male body?
Production and secretion of testosterone
Define melanocyte stimulating hormones
Peptide hormones produced in skin, ant pituitary and parts of brain
What inhibits release of Melanocyte Stimulating Hormone?
Dopamine inhibits MSH release from Ant. Pit.
What does MSH do within human body?
Pigmentation of skin cells
Suppression of appetite
What stimulates the release of Thyroid Stimulating Hormone?
TRH from hypothalamus stimulates TSH release from Ant. Pit.
What inhibits release of TRH?
Increased T3/T4
Inhibs TSH production too
Reduction of TRH and TSH causes suppression of what synthesis?
T3/T4
What are the two parts of the posterior pituitary?
Pars Nervosa- bulbar part
Infundibular stalk- connects to pituitary gland
What hormones does the posterior pituitary make?
None, storage only
Stores ADH and Oxytocin
What is normal urine output w/ ADH?
1-2L
w/out- 20L/day
What effect does ADH have on BP?
Increases BP by vasoconstriction of arterioles
ADH secreted depends on what 2 factors?
Blood osmotic pressure
Blood volume
4 causes of high osmotic pressure
Dehydration
Hemorrhage
Diarrhea
Excessive sweating
Define osmotic pressure
Define osmoreceptor
Press: pressure solutes are causing in plasma
Receptor: baroreceptor in hypothalamus for measuring osmotic pressure
What are the 3 action sites for ADH?
Kidneys
Sudoriferous glands
Vascular smooth muscle
What factors alter ADH secretion?
Pain
Stress
Trauma
Anxiety
Morphine
Tranquilizers
Anesthetics
Nicotine
Suspected role of Oxytocin outside of pregnancy/milk ejection?
Ability to emotionally/socially bond w/ others
What stimulates TSH secretion?
TRH from hypthalamus
What causes synthesis of thyroid hormone?
TSH presence
What causes inhibition of TSH
Negative feedback to hypothalamus to stop/slow TRH which tells Ant. Pit. to slow TSH release
Anything that increases cellular energy demand with cause an increase in production of _____
T3 and T4
What is the largest “pure” endocrine gland?
Thyroid
How do the wings of the thyroid gland connect?
Isthmus, anterior to trachea
What is the 3rd lobe of the thyroid called that’s found in 50% of people?
Pyramidal lobe
What are the functional units of the thyroid?
Follicles
Inside of follicle is called a colloid
What do parafollicular cells create?
Calcitonin
Made in thyroid, not A thyroid hormone
Characteristics of T4
Inactive thyroid hormone
More abundant, less potent
Characteristics of T3
Active form of thyroid hormone
Less abundant, more potent
Synthesis of T3 and T4
Watch and learn
Difference between TGB and TBG
TGB: thryoglobulin, glue that binds MIT, DIT, T3 and T4
TBG: thyroxine binding globulin, transport protein that carries T3/T4 to target cell after synthesis
What are the actions of T3/T4
Increase basal metabolic rate Stimulates synthesis of Na/K pumps Regulate metabolism (protein synth) Enhance catecholamine action Work w/ hGH and insulin to accelerate body growth (nervous/skeletal)
Increased basal metabolic rate causes metabolism of what 3 things?
carbs
proteins
lipids
Increased number of Na/K pumps has what end result?
Increased ATP production and consumption
Heat is byproduct and used by body
What effect do T3/T4 have on epi/norepi?
T3/4 upregulate beta adrenergic receptors
Explains why hyperthyroid PTs are tachy and hypertension
T3/T4 deficiency during childhood has what consequences?
Mental retardation
Stunted bone growth
Location of Parafollicular cells
Outside of follicular cells
Inside thyroid
Function of parafollicular cells
Synth/secrete calcitonin
What stimulates/inhibits release of Calcitonin
Stim: high Ca+ and HPO4 serum levels
Inhib: low Ca+ and HPO4 serum levels
Define resorption
Using/losing a substance
Breakdown of bone matrix by osteoclast to increase plasma Ca+ levels
Define absorption/reabsorption
Process of gaining something
Osteoblast absorbing Ca+ from blood to build bone matrix
How does calcitonin regulate Ca levels?
Inhibits osteoclasts
Increases osteoblasts
Decrease Ca absorption in gut
Increase Ca loss in urine
How does calcitonin increase Ca+ loss in urine?
Prevents cells in distal convoluted tubule from reabsorbing Ca
Where are parathyroid glands located?
ON thyroid gland
How many parathyroid glands are there?
What are their functional components?
4 Principle cells (aka Chief cells)
What is the purpose of Principle cells?
Secrete PTH
What stimulates/inhibits PTH release?
Inhib: High serum Ca
Stim: Low serum Ca
How does PTH regulate Ca levels?
Increase osteoclast
Inhibits osteoblast
Increase Ca absorption in gut
Decrease Ca loss in urine
What are the two sections of Adrenal Glands
Cortex: large, peripherally located
Medulla: small, centrally located
What stimulates Adrenal Cortex to make it’s hormones?
Hypothalamus secretes CRH
Ant Pit releases ACTH
Impacts adrenal cortex
What 3 hormones are made in what zones of the adrenal cortex?
Glomerulus- mineralcorticoids
Fasciculata- glucocorticoids
Reticularis- androgens
What is secreted by Zona Glomerulosa and what function
Mineralcorticoids- aldosterone
Affects mineral homeostasis
Mineralcorticoids from Zona Glomerulosa promotes what two things?
Reabsorption of Na in kidneys
Promotes loss of K and H in urine
What stimulates the secretion of Aldosterone
Elevated K and H levels
Low BP
What inhibits secretion of aldosterone
Low K and H levels
High BP
What system stimulates aldosterone release?
RAAS
Steps of RAAS
Low BP sensed by kidneys
Kidneys secrete renin
Renin causes angiotensinogen->angiotensin-I
Angiotensin-I goes to lungs where its split to Angiotensis-II by ACE
Where is angiotensinogen made?
Liver
How does Angiotensin-II increase BP
Stim aldosterone production
Increases sympathetic NS
Arteriolar constriction
Release of ADH
What is secreted from Zona Fasciculata
Glucocorticoids-
Cortisol
Corticosterone
Cortisone
What effects do gluccocorticoids have on the body?
Regain homeostasis after stress event
What functions do glucocorticoids have?
- Protein catabolism (all cells except liver)
- Gluconeogensis (aa->glucose)
- Lipolysis (shifts body to lipid catabolism)
- Immune suppression (decreases eosinophils and atrophy of lymphatic tissue, decreases plasma cells)
- Anti-inflammation(inhibs prostaglandin and leukotriene precursors, inhibs IL-2, proliferation of T cells, inibs release of histamine and serotonin and platelets)
- Inhibits bone formation (dec Type I collagen, dec osteoblast, dec intestinal reabsorption of Ca)
What does the Zona Reticularis secrete?
What are these secretions later turned into?
Weak androgens: DHEA and DHT
Testosterone
Estrogen
Characteristics of DHEA
Weak androgenic effect
Precursor for numerous hormones
Androsternedione, testosterone, DHT, estrogen
Characteristics of Androstenedione
Weak androgenic effect
Converted to testosterone or estrogen (precursor for estradiol
Characteristics of DHT
More potent androgen than testosterone
Made from conversion of testosterone
Is active in tissues where testosterone is not
What type of cells make up the middle region of the adrenal gland (adrenal medulla)
Chromaffin Cells- adrenal medulla functional cells
What are the functions of Chromaffin cells?
Synthesize and secrete Epi and Norepi
What’s more potent, epi or norepi?
norepi- precursor to epi
epi- more potent and abundant
Chromaffin cells are considered modified cells of what system?
Sympathetic ganglion of ANS
Sympathetic NS stimulates chromaffin cells through what nerves?
Splachnic nerves
Effects of catecholamines on the body?
Intensify Symapthetic NS
Dilation- heart, brain, lungs, muscle
Constriction- GI, kidneys, skin
Liver and muscle conversion of glycogen to glucose
The pancreas is _% endocrine and _% exocrine
Endo- 5%
Exo- 95%
What part of the intestine does the pancreas rest?
Curve of duodenum
Where are the endocrine cells within the pancreas?
Middle of exocrine acini are the Islets of Langerhans
What are the 4 types of Islet cells in the pancreas?
A- secrete glucagon
B- secrete insulin
D- secrete somatostatin
F- (aka PP cell) secrete pancreatic polypeptide
Function of glucagon
raise blood sugar levels
Pancreatic receptor detect hypoglycemia and release glucagon
Stims liver glycogenolysis
Stims liver gluconeogenesis
Stim lipolysis
What inhibits release of glucagon?
Negative feedback
increased serum glucose levels
Function of insulin
lowers blood glucose levels
Presence of food in small intestine triggers release of GDIP (aka GIP) which stims insulin release from pancreas
What are the 4 functions insulin does?
Glucose uptake in cells
Stims glycolysis
Stims gluconeogenesis
Triglyceride/protein synthesis
What inhibits release of insulin?
Insulin decreases w/ decreased serum glucose levels
Function of somatostatin
AKA GHIH
Paracrine action inhibiting insulin and glucagon release
Endocrine action inhibiting release of hGH
Function of pancreatic polypeptide
Inhibits somatostatin release
Inhibits gallbladder contraction
Inhibits bicarb secretion
Explain blood sugar during a fasted state
Hypoglycemia inhibits release of insulin
Stimulates release of glucagon
Glucagon stims hepatocyte conversion of glycogen->glucose (glycogenolysis)
Explain blood sugar during fed state
Hyperglycemia inhibits release of glucagon, stim release of insulin
Stims cell uptake of glucose
Speeds glucose->glycogen
Lipogenesis
What are the 4 hormones synthesized and secreted by the ovaries?
Estrogen Progesterone Inhibin Relaxin Inhibin and relaxin only made/secreted in bulk during pregnancy
When estrogen, progesterone, LH and FSH combine they regulate what three things
Regulate menstrual cycle
Maintain pregnancy
Prepare mammary glands for lactation
What are the functions of inhibin and relaxin during pregnancy?
Inhibin: Inhibits FSH, deters follicle development
Relaxin: Relaxes cervix and pubic symphysis cartilage to aid in delivery
What two hormones do the testes form?
Testosterone
Inhibin
3 functions of testosterone
Stims decent of testes before birth
Regulates production of sperm
Secondary sex characteristics
Functions of inhibin in males?
Inhibits FSH, spermatogenesis
Function and source of production of Cholecalciferol
Skin
modified to form Vit D
Four specific hormones released by Thymus
Thymosin
Thymic humoral factor
Thymic factor
Thymopoietin
4 miscellaneous hormones released by liver?
IGF-1
Angiotensinogen- inc BP
Thrombopoietin- stims platelet production
Hepcidin- block release of Fe into body fluids
Source and function of Cholecystokinin
Secreted by I cells of small int.
Stim by: fats and proteins (monoglycerides, fatty acids, small peptides, amino acids)
Causes gallbladder contractions
Slows gastric emptying
Stims secretion of pancreatic enzymes, bicarb, exocrine pancreas and gallbladder growth
Satiety*
Source and function of Glucose-dependent Insulinotropic Peptide (aka gastric inhibitory peptide)
Secreted by K cells of small intestines
Stim by presence of glucose, fatty acids or aa
Stimulates release of insulin
Inhibits H+ ion secretion
Source and function of secretin
Secreted by S cells of small intestine
Stimulated by presence of fatty acids, acidic contents
Stimulates secretion of BiCarb from pancreas and gallbladder
Inhibits gastrin effects
Source and function of Eicosanoids
Found in all body cells EXCEPT RBCs
Paracrine/autocrine hormones in response to mechanical/chemical stimuli
Prostaglandins- tons of effects
Leukotrienes- WBC chemotaxis stimulation
Source and function of histamine
Synth in any tissue w/ mast cells and platelets
Stimulated by trauma and immune response
Contract smooth muscles (lungs, uterus, stomach)
Lowers BP
Stimulates gastric acid release
Increase permeability in capillaries and post-cap venules
Source and function of serotonin
Synthesized in small intestine, brain and CNS
Platelets will uptake free serotonin for storage
Mood, anxiety, appetite, temp, eating/sex behavior
Body and gastro movement
Can be Vasoconstrictor/dilator
What are the two types of stress
Eustress
Distress
What is the process of the body counteracting stress called
What controls this process?
General Adaptation Syndrome
Hypothalamus
What are the 3 phases of stress response
Alarm
Resistance
Exhaustion
Define functional medicine
Addresses root cause of disease
Treats whole system
Still considered “alternative medicine”
Aging endocrine system has what effects on the body
dec hGH= atrophy
dec T3/T4= dec metabolism, inc fat, hypothyroidism
dec insulin, dec receptor sensitivity= hyperglycemia
dec ovary size, dec estrogen= osteoperosis, atherosclerosis, hyperlipidemia
dec testes size= same amount of sperm, altered morphology and motility
Inc TRH/TSH
Inc PTH= dec calcitonin, dec calcitriol